Summary:
The diff moves an invocation of `_synchronizeAllSettings` from the constructor to `setBridge`. The side-effects of `_synchronizeAllSettings` rely on a bridge not being nil, so we need to ensure that the bridge is assigned to the instance before calling `_synchronizeAllSettings`.
Before the fix, enabling JavaScript debugger caused a stale and opening many copies of a debugger in Chrome.
Changelog: [Internal] Fixed race and possible stale in RCTDevSettings
Reviewed By: RSNara
Differential Revision: D18379596
fbshipit-source-id: 9f64b9bc5426720948113de61bc9ccc8c39193b4